Ground data receipt and fan out for a satellite communication system

Abstract

A system includes a transmitter and a processor. The processor is configured to receive data at a satellite; determine a satellite time for the satellite based at least in part on the data; adjust a local time reference of the satellite; and provide the satellite time from the satellite to another satellite in a constellation using the transmitter.

What is claimed is: 
     
         1 . A system, comprising:
 a transmitter; and   a processor configured to:
 receive data at a satellite; 
 determine a satellite time for the satellite based at least in part on the data; 
 adjust a local time reference of the satellite; and 
 provide the satellite time from the satellite to another satellite in a constellation using the transmitter. 
   
     
     
         2 . The system of  claim 1 , wherein receiving the data comprises acquiring a communication link. 
     
     
         3 . The system of  claim 2 , wherein receiving the data comprises receiving a time-of-day using the communication link. 
     
     
         4 . The system of  claim 3 , wherein the time-of-day has a resolution of 1 ps or less and an accuracy of 100 ps or less. 
     
     
         5 . The system of  claim 3 , wherein receiving the time-of-day comprises receiving a first short pulse or first high bandwidth signal. 
     
     
         6 . The system of  claim 5 , wherein the short pulse is at most 100 ps. 
     
     
         7 . The system of  claim 5 , wherein the high bandwidth signal is at least 10 GHz. 
     
     
         8 . The system of  claim 5 , wherein receiving the time-of-day comprises transmitting a second short pulse or second high bandwidth signal after a precise time delay from a time of arrival of the first short pulse or the first high bandwidth signal. 
     
     
         9 . The system of  claim 8 , wherein the precise time delay comprises a time delay with a precision of 100 ps or less. 
     
     
         10 . The system of  claim 8 , wherein receiving the time-of-day comprises determining a propagation time based on the second short pulse or the second high bandwidth signal. 
     
     
         11 . The system of  claim 10 , wherein the propagation time is determined with an accuracy of 100 ps or less. 
     
     
         12 . The system of  claim 10 , wherein determining the satellite time is based on the propagation time. 
     
     
         13 . The system of  claim 12 , wherein the satellite time is adjusted for the other satellite based on the propagation time and transmitted to the other satellite. 
     
     
         14 . The system of  claim 1 , wherein receiving the data at the satellite is from a ground station. 
     
     
         15 . The system of  claim 1 , wherein receiving the data at the satellite is from the other satellite. 
     
     
         16 . The system of  claim 1 , wherein providing the satellite time uses an optical link. 
     
     
         17 . A method, comprising:
 receiving data at a satellite;   determining, using a processor, a satellite time for the satellite based at least in part on the data;   adjusting a local time reference of the satellite; and   providing the satellite time from the satellite to an other satellite in a constellation using a transmitter.   
     
     
         18 . A computer program product embodied in a non-transitory computer readable medium and comprising computer instructions for:
 receiving data at a satellite;   determining, using a processor, a satellite time for the satellite based at least in part on the data;   adjusting a local time reference of the satellite; and   providing the satellite time from the satellite to an other satellite in a constellation using a transmitter.